and how much they weigh. How many do you have?
I've got three boys. The 15 month old goes in the center rear because it works best with the child seat.
I let the 5 year old sit in a booster seat on one side or the other using the shoulder belt, and the 7 year old can sit up front.
If we are on a long road trip, I'll put them all in child car seats/boosters, in the back.
I do love the fact that E34 rear seats have the latch on the outboard part of the rear seat. I makes a huge difference when getting them in and out.
JD